More and more integrated circuits (IC's), including signal IC's and microwave IC's, are being constructed using high density interconnect (HDI) technology. As described in commonly assigned U.S. Pat. No. 4,783,695 of Eichelberger et al., issued Nov. 8, 1988, which is incorporated by reference herein, and in other related patents, HDI structures offer many advantages in the compact assembly of, for example, digital and other electronic systems. Furthermore, as described in commonly assigned U.S. patent application Ser. No. 07/504,821 of Kornrumpf et al., filed Apr. 5, 1990, now abandoned in favor of Continuation application Ser. No. 07/869,090, filed Apr. 14, 1992, now U.S. Pat. No. 5,355,102, issued Oct. 11, 1994, HDI technology has been extended to microwave systems. Furthermore, HDI technology has been extended to support the building of power circuits, as described in commonly assigned U.S. patent application Ser. No. 08/002,374 of Neugebauer et al., filed Jan. 8, 1993, now abandoned U.S. Pat. No. 5,384,691 issued Jun. 24, 1995. The Neugebauer et al. application describes how HDI may be used to integrate diverse power components, with the magnetic elements being treated as discrete elements.
In order to completely integrate a power supply with HDI digital and microwave modules, it is desirable to be able to construct the power supply, including magnetic components, using the same technology, i.e., HDI. In order to build magnetic components in an HDI structure, the height of the magnetic component must be very small, e.g., less than about 0.1 inch. Such thin magnetic components generally require multi-pole core structures, such as described in commonly assigned U.S. Pat. No. 5,126,715 of Yerman and Roshen, issued Jun. 30, 1992 and incorporated by reference herein.
In addition to lumped magnetic components, it is also desirable to be able to construct distributed electromagnetic circuit components using HDI technology for integration in, for example, HDI microwave modules.